Impact tool



July 7, 1931. J. R. SANDAG'E IMPACT TOOL 2 smu -sheet 1 Filed Jan. 28,192 6 July 7, 1931.

J. R. SANDAGE IMPACT TOOL Filed Jan. 28, 1926 2 Sheets-Sheet 2 I laPatented July 7, 1931 PATENT OFFICE JACOB R. SAN D'AGE, OF CHICAGO, ILLINOIS IMPACT TOOL Application filed January 28, 1926. Serial No. 84,425.

- This invention relates to impact drills or similar tools, in which thedrill or the tool is subjected to the impacts of a rapidly reciprocatingplunger or hammer, thereby to cause the drill or other tool to performthe desired work.

Generally stated, the object of the invention is to provide a novel andimproved means for delivering the impacts to the drill or other tool, ina rapid and satisfactory manner.

A special object is to provide a novel and improved construction andarrangement whereby the impact-producing instrumentalities are operatedby electric power. I I Another object is to provide a novel and improvedconstruction and arrangement whereby the reaction from the impacts, inthe hammer or plunger, is cushioned, and

thus prevented from producing injurious or undesirable vibration of theapparatus.

It is also an object to provide certain details and features ofconstruction and combinations tending to increase the general efiiciencyand the desirability of an impact tool apparatus of this particularcharacter.

To these and other useful ends, the invention consists in the mattershereinafter set forth and claimed and shown in the accompanyingdrawings, in which:

\ Fig. 1 is a plan view of an impact tool apparatus embodying theprinciples of the invention, in'partial' and horizontal section, thesection being taken on line 1-1 in Fig.

85 2 of the drawings. 7

Fig. 2 of the drawings is a vertical longi: tudinal section on line 2- 2in Fig. 1.

Fig. 3 is a view similar to Fig 2, on a larger scale, with certainportions broken away for convenience of illustration.

Fig. 4 is a transverse vertical section on line 44 in Fig. 3.

Fig. 5 is a transverse vertical section on line 5-5 in Fig. 3.

As thus illustrated, the invention comprises a hollow body 1 having-achuck 2 at one end to receive the drill or other tool 3 in position tobe operated by, the impact mechanism. Said mechanism comprises a 60reciprocating head 4, which reciprocates in the bore 5 of the body 1,and which is re ciprocated by the two pitmen 6 connected to the bevelgears 7, whereby these bevel \gears act as crank plates to actuate thepitmen and thereby reciprocate said head. These bevel gears are rotatedin opposite directions by the interposed bevel pinion 8, and" the latteris operated by an electric motor 9 of any suitable or desired character,mounted within the casing 10 which forms a part of the body of theapparatus. Thus when one pitman is up the other is down, as the bevelgears 7 rotate in opposite directions, and in this way the lateralthrust of one pitman, on the head 4, is counteracted by the lateralthrust of the other pitman, whereby the lateral thrust of the crankmeans thus provided is balanced, with the result that in effect the head4 is always subject to a straight push or pull, and in efiect is notsubject to any lateral thrust.

The hammer or plunger 11 reciprocates in the bore 12 of the body, anddelivers the impacts to the inner end of the drill or other tool 3, in amanner that can be readily understood The stem portion 13 of said hammeror plunger extends through a guide portion 14 in the end of the head 4,this guide portion forming inner and outer shoulders for the coilsprings 15 and 16 onsaid stem. The spring 15, it will be seen, isinterposed between the end of the head 4 and the shoulder 17 on thehammer or plunger, while the spring 16 is interposed between the guide14 and the nut 18 screwed on to the end of the stem 13, as shown.Preferably, a spline 19 is provided on the stem 13, to engage a groovein the guide 14, thereby to prevent rotation of the hammer or plunger.

Thus, with the construction shown and described, which is illustrativeof the inven tion, the rapid reciprocation of the head 4, by theelectric motor, through the medium ofthe' doublevcrank mechanism, willcause tha'hammer or plunger 1*1 J to -re'ciprocate rapidly, but with asomewhat greater throw, of course, inasmuch as the momentum of thehammer or plunger will carry it on a distance beyond the end of thestroke of the 7 head 4, inasmuch as the spring 16 will be compressed,thus permitting the hammer or plunger to travel far enough forward todeliver the desired impact upon the inner end of the drill or othertool. Of course, when the head 4 reaches the end of its stroke towardthe crank plates, the momentum of the plunger or hammerll will thencarry it on a slight distance, compressing spring 15,,

whereby the plunger or hammer travels a distance farther at each end ofits stroke than does the reciprocating head. It is desirable, as shown,to have the spring 16 somewhat longer than the spring 15, as a greateroverthrow of the hammer or plunger is desired at the end of its stroketoward the drill or other tool. Therefore, when the hammer or plungeractually delivers the blow or impact upon the inner end of the drill orother tool, the spring 16 is under compression, and the spring 15 isexpanded and the reaction from the blow in the hammer iself ispractically not communicated to any extent to the actuating mechanism.In other words, it is very much as though the hammer or plunger wasdisconnected and thrown forward a distance, after the head 4 stopsmoving forward, and hence the reciprocating head 4 and the crankmechanism are not subject to the reaction from impacts delivered by thehammer or plunger ppon the inner end of the drill or other too Inaddition, as shown, the ifnpact too] apparatus is conveniently operatedby electric power through the medium of an ordinary rotary electricmotor, the rotation of the motor being ultimately converted ortranslated into rapid reciprocation of the hammer or plunger to deliverthe desired impacts upon the inner end of the drill or other tool.

It will be understood, of course, that the body of the apparatus can beconstructed in any suitable or desired way. It will be observed that thebevel gears 7 have their journals 20 mounted in suitable bearings 21formed on the casing or body of the apparatus, nd bearings 22 may beinterposed, if desire between the bevel gears 7 and the inner side ofthe casing, thereby to take the axial thrust of these two gears,produced by the pinion 8, and thus insure smooth and easy running of thecrank mechanism. The ball bearings 22 may be of any suitable character.7

Thus'the hammer delivers the impact by momentum alone, for as soon asthe member 4 stops movin forward, after reaching the end of its stro e,it is then merely the momentum of the hammer 11 which carries it forwardto an extent sufiicient to deliver the required impact uponrthe innerend of.

the tool. The momentum of the hammer 11 compresses the spring 16, butthe momentum is greater than the resistance of the spring, and hencethespring does not expand and return the hammer to its normal position,relative to the member 4, until after the latter has reversed its motionand has traveled backward a distance. -Thus, thereaction from theimpacts is prevented from extending back into the operating mechanism,and cannot reach the motor,'

which latter is axially aligned with the tool, the said motor and thepinion 8 and the hammer 11 and the tool 3, and also the springs 15 and16, and the member 4, being all "axially aligned in the manner shown.

Any suitable means (not shown) can be employed for gradually rotatingthe tool 3, about its longitudinal axis, which axis is also the axis ofthe motor, as explained, if such is necessary or desirable. Means forgradually rotating the tool, during the impacts, and while the tool isin use, are well known and need no description or illustration thereof.

It will be seen that the transverse pivot formed at 23, where the twopitman 6 con nect to the member 4, is between the spring 16 and thecrank plate mechanism, so that the said spring is entirely in'front ofsaid axis Furthermore, and by actuating the bevel pinion 8, power iscommunicated directly to each crank plate, and no power is communicatedfrom one crank plate 7 to the other crank plate 7, each crank plateoperating independently of the other to transmit power through itsallotted pitman 6 to reciprocate the member 4 in the manner explained.The pivot 23 is removable through the openings 24 in the sides of thecasing, and the motor 9 and the pinion 8 are removable as a unit bymerel unscrewing the ring 25 which is screwe on to the end of the casingsection 10in the manner shown. The rear end of the member 4 must beopen, of course, as shown, as the spring 10 1s mserted in place throughthis open, end, and also the nut 18, and thus there is access throu hthis open end to permit both assembling and removal of the parts. Whenthe pivot 23 is pulled out, and the nut 18 is removed, the hammer canthen be removed from the front end of the member 4, and the spring 16can then be pulled out of said open rear end. It will be seen that ofthree sections, detachably bolted to gether, the middle split or dividedsection removably enclosing the crank plate mechanism, one end sectionenclosing the motor, and the other end section enclosing the recirocating hammer mechanism.

ithout disclaiminganything, and without prejudice to anynoveltydisclosed, what I claim as my invention is: I

1. In an impact tool apparatus, the comternally supported and guidedmember open at its rear end and formed at its front end with a bearingfor said hammer, in which bearing the hammer reciprocates endwise,spring means engaging said hammer and said bearing to ca'use the hammerto reciprocate and have a longer stroke than said member, causing thehammer to continue moving forward by momentum alone after said memberreaches the end of its forward ,posed entirely in front of said pivot.

2. A structure as specified in claim 1, said spring means conipnsing acoil spring enclosed in said member, and said hammer having a stemextending through said bearing and through said coil spring, with meanson said stem'to form a shoulder to engage one end of the spring, wherebysaid spring reciprocates relatively to said tool fand is compressed bythe momentum of the ham 4 whereby said instrumentallties'except sa1dmer.

3. A structure as specified in claim 1, said spring means comprising twocoil springs, a.

portion of said member'forming said bearing being interposed betweensaid springs, and said hammer havin a stem extending through bothsprings an through said bearing, whereby one spring is compressed by themomentum of the hammer at the end of' the stroke in one direction, andthe other s ring is likewise compressed at the end 0 the stroke in theopposite direction, whereby both springs reciprocate relatively to saidtool.

4. A structure as specified in claim 1, said instrumentalitiescomprising an electric motor the axis of which is coincident with thelongitudinal axis of said bearing and said spring means, and comprisingpower transmitting means between said motor and said hollow member, saidpower transmitting means having an axis transverse to said longitudinalaxis, communicating power throiwh said spring means to the hammer.

5. K structure as specified in claim 1, said instrumentalitiescomprising a double crank mechanism, with pitmen disposed side by sidebetween the cranks and connecting. the cranks to said pivot, wherebythe" cranks between said rotating means and said hollow.

member, communicating power through said sprin means to the hammer.

6. 3 structure as specified in claim 1, said instrumentalitiescomprising two bevel gears serving as crank plates pitmen disposed sideby side between the gears and connecting the cranks to said pivot, theitmen extending into 'said member, so t at said gears actuate saidmember, a bevel pinion interposed between said bevel gears, spacing thegears far enough apart to accommodate the pitmen between them, means torotate said pinion and thereby rotate said gears in opposite directions,thereby to balance the lateral thrust of sald pitmen on said member, andwhereby the thrust of said spring means on said bearing is sustainedequally by both bevel gears, in combination with a casing formingtransverse opposite split bearings for said gears, said casing havingprovisions pinion are removable intact independently of said tool, saidcranks being disposed between said rotating means and 52nd hollowmember, communicating power through said sp17'ing means to the hammer.

having sections and o structure as specified in claim 1, saidinstrumentalities comprising two bevel ears serving as crank plates,pitmen dispose side by side between the gears and connectmg the cranksto said member, the pitmen extending into said member, so that saldgears actuate said member, a bevel pinion interposed between said bevelgears, spacing the gears far enough apart toaccommodate the pitmenbetween them, and comprising also ineans to rotate said pinion andthereb rotate said gears in opposite directions, t ereby to balance thelateral thrust ofsaid pitmen onsaid member, and whereby the thrust ofsaid spring means on said bearing is sustained equally by both bevelgears, and an pendent-1y of said tool, said cranks being disposedbetween said rotating means and said hollow member, communicating powerthrough said spring means to the hammer. 8. A structure as specified inclaim 1, in combination with a body forming a' sectional casing forenclosing all of said specified elements, said casing having threeconnected separable sections, said sections disposed end to end, and themiddle section being divided centrally and longitudinally thereof in aplane coincident with the longitudinal axis of said apparatus andthereby removably enclosing said instrumentalities, form- 'ingtransverse opposite split bearings ior parts of said instrumentalities.

Specification signed this 26th day of January, 1926.

JACOB R. SANDAGE.

